(a) Field of the Invention
The present invention relates to a method for data transmission. More particularly, the present invention relates to a method and an apparatus for transmitting data in direct device-to-device communication.
(b) Description of the Related Art
In a wireless communication system, when reception/transmission for data between terminals (e.g., between vehicles) is performed, reliability and delay time should be considered. Recently, along with the development of wireless communication systems, device-to-device (D2D) communication has been issued. Particularly, as the Long Term Evolution (LTE)-Advanced technology becomes commercially available, methods related to the D2D communication based on this have been researched. In the D2D communication, without the support of a network device such as a base station, terminals can form and maintain a D2D communication network by using distributed and limited radio resources, and operations such as synchronization, peer discovery, paging, and data traffic communication are performed.
This D2D communication operates based on proximity, and has many advantages of increased efficiency of network resources, reduced power consumption of a terminal, expanded communication coverage, and the like, but reliability and delay time are relatively low. In D2D communication, for example, in a service in which data is transmitted/received between vehicles, higher reliability and higher delay time are required. Furthermore, high movement speed needs to be considered. When the D2D communication is performed with high movement speed, there is a difficulty in meeting requirements for some modulation coding schemes (MCS) in initial transmission. In addition, when retransmitting, requirements for movement speed and other requirements may not be satisfied.
Accordingly, to meet requirements for high reliability and delay time for various movement speeds, the transmission scheme needs to be changed.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.